Its value varied, but it was standardized in the late empire as 1.2829 kilograms.
[4] In Greece, the oka (οκά, plural οκάδες) was standardized at 1.282 kg and remained in use until traditional units were abolished on March 31, 1953[5]—the metric system had been adopted in 1876, but the older units remained in use.
In Tripolitania, it weighed 1.2208 kg, equal to 2½ artals.
In Wallachia, it was 1.283 liters of liquid and 1.537 L of grain (dry measure).
In Greece, an oka of oil was 1.280 kg, which would have translated to about 1.340 litres (at 0.916 kg/l).